The available size calculation did not handle wraparound correctly. Also, the underrun handling code confused slave_buffer_size with slave_boundary, causing another integer overflow that results in too many samples being skipped.
Signed-off-by: Maarten Baert maarten-baert@hotmail.com --- src/pcm/pcm_dmix.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/src/pcm/pcm_dmix.c b/src/pcm/pcm_dmix.c index 843fa316..b5fdb240 100644 --- a/src/pcm/pcm_dmix.c +++ b/src/pcm/pcm_dmix.c @@ -315,11 +315,12 @@ static void snd_pcm_dmix_sync_area(snd_pcm_t *pcm) /* check the available size in the local buffer * last_appl_ptr keeps the last updated position */ - size = dmix->appl_ptr - dmix->last_appl_ptr; + if (dmix->appl_ptr >= dmix->last_appl_ptr) + size = dmix->appl_ptr - dmix->last_appl_ptr; + else + size = dmix->appl_ptr + (pcm->boundary - dmix->last_appl_ptr); if (! size) return; - if (size >= pcm->boundary / 2) - size = pcm->boundary - size;
/* the slave_app_ptr can be far behind the slave_hw_ptr */ /* reduce mixing and errors here - just skip not catched writes */ @@ -328,18 +329,19 @@ static void snd_pcm_dmix_sync_area(snd_pcm_t *pcm) else slave_size = dmix->slave_appl_ptr + (dmix->slave_boundary - dmix->slave_hw_ptr); if (slave_size > dmix->slave_buffer_size) { - transfer = dmix->slave_buffer_size - slave_size; + transfer = dmix->slave_boundary - slave_size; if (transfer > size) transfer = size; dmix->last_appl_ptr += transfer; dmix->last_appl_ptr %= pcm->boundary; dmix->slave_appl_ptr += transfer; dmix->slave_appl_ptr %= dmix->slave_boundary; - size = dmix->appl_ptr - dmix->last_appl_ptr; + if (dmix->appl_ptr >= dmix->last_appl_ptr) + size = dmix->appl_ptr - dmix->last_appl_ptr; + else + size = dmix->appl_ptr + (pcm->boundary - dmix->last_appl_ptr); if (! size) return; - if (size >= pcm->boundary / 2) - size = pcm->boundary - size; }
/* check the available size in the slave PCM buffer */